Traditionally, vehicles include multiple systems that regulate overall operation of the vehicle. For example, the vehicle includes a power plant or torque source (e.g., an internal combustion engine and/or an electric machine) that generates drive torque, an energy storage device (e.g., battery pack) that provides electrical energy, a transmission that distributes the drive torque to driven wheels and various other systems. Each of the systems includes an associated control module or modules that communicate with one another to regulate operation of the vehicle.
In some vehicle systems, such as a hybrid vehicle system, an engine control module (ECM) and a hybrid control module (HCM) are provided as part of a distributed controller system. To optimize the mix of electric motor and engine torque to meet driver demand, while also minimizing fuel consumption, the HCM, or optimizer control module, must know the torque available from both the electric motor and the engine at any given point in time. If the engine includes a camshaft phaser, the torque available from the engine can strongly depend on the ability of the phaser to move the camshaft.
In a distributed controller system, if the estimated available engine torque is calculated in a controller other than the optimizer control module, there is a time period required to communicate the calculated available torques to the optimizer control module. Because the cam phaser can almost instantly switch from disabled to enabled and vice-versa, there can be a period of uncertainty about the actual available torque from the engine. This could result in suboptimal transmission gear selection and/or unreasonable delay in allowing full powertrain torque development, for example.